New routes to N-(diethoxyphosphoryl)imines derived from enolizable carbonyl
compounds have been investigated. Three different procedures were studied:
(i) the aza-Claisen condensation of ethyl-[N-(diethoxyphosphoryl)]-formimi
date with enolizable ketones, (ii) the reaction between diethyl N-sulfinylp
hosphoramidate and aliphatic aldehydes, and (iii) the thermally induced rea
ction of diethyl phosphoramidate with ketone diethyl acetals. With two exce
ptions in all cases the products were identified as diethyl 1-alkenylphosph
oramidates with no spectroscopically detectable amounts of imine tautomers.
The aza-Claisen condensation can be recommended as a simple and effective
route to diethyl 1-alkenyl-3-oxophosphoramidates. (C) 2000 Elsevier Science
Ltd. All rights reserved.